Zen master Dahui once said: "A great doubt will definitely be followed by a great awakening." In other words, it is only when we feel confused, frustrated, and uncertain— Dahui's biting the iron bar—that we are making the proper effort for achieving enlightenment or satori. To be sure, we need to give this some thought. There is something profound here. For one thing, if you already know the answer, what’s there to learn or to be enlightened about? I just found this in my notes the other day.
“When we tell you that 2 + 2 = 4, we are not communicating: You already knew that. You had no uncertainty, so we transmitted no information. Information is communicated only when the receiver is uncertain about the content of the message. The more uncertain the receiver, the more potential there is for information transmission” (Roy Lachman, C. Butterfield, and Janet L. Lachman, Cognitive Psychology and Information Processing: An Introduction, 136). (Emphasis is mine.)
Zen’s so-called Mind to Mind transmission is certainly the transmission of something. Not a material object, but more of a spiritual communication. I will awaken, exactly, to what the Buddha awakened to. But my awakening depends upon great uncertainty. I have to know that I don’t know what this Buddha Mind is. I am stumbling around confused, frustrated and in a deep pit of doubt. As I have said before, I have to go to my wits’ end. I even have to give up hope in sitting in formal zazen—as if this will help me to awaken to Buddha Mind. I must even give up the belief that there is, fundamentally, no enlightenment which is still a holding on to something.
I was just thinking about a baby. Maybe a baby has its own kind of great doubt. With its baby doubt it is fully open to information, especially, language and what these odd sounds mean. For the serious Zen student they need to be more like a baby than a scholar. There is a mystery how a baby learns—from doubt to awakening as a human being.